In recent years there has been a trend to build automobiles with a single body construction in which the body of the vehicle performs as the frame for the rest of the components.
Previously, vehicles were built on a channel frame generally rectangular in shape and parallel to the ground or other rolling surface. In this prior construction, the wheels and axles were supported under the frame and the body and engine components were supported on top of the frame and fastened thereto. In such prior construction the various components could be detached from the frame in a repair or rebuilding process and once removed could be worked on separately.
However, in unibody construction the various components are a part of the body itself and therefore the components are difficult to remove. This is particularly true in connection with the hinges for the doors.
The hinges in automobile and vehicle doors usually comprise the stationary element fastened to the body, a rotary element fastened to the door, and a pin vertically oriented passing down through folded, vertically cylindrical trunion portions that are separately formed on the stationary portion and the rotary portion. In unibody construction the hinge components other than the hinge pin cannot be removed since they are welded into the body or into the door to become unitized with the particular member.
As a consequence of this construction, when it is necessary to remove the doors in repair or reconstruction operations the hinge pins must be removed from the hinges so that the doors can be removed.
Hinge pins generally come in two different basic forms. One form is the hollow pin pressure fitted within the vertical trunion portions as shown in U. S. Pat. No. 4,432,125 Monteleone et al. As shown in that patent, it is necessary to drive the hinge pin out of the trunions and this reference patent discloses a air hammer driven tool for this purpose.
On the other hand, hinge pins on many models of unibody built automobiles are of the solid cylindrical pin with an enlarged head of the type shown in U. S. Pat. No. 4,627,141 Teske (FIG. 7). This reference discloses a special air hammer driven tool to assist in the removal of "headed" pins of the second type.
This invention is directed to the removal of headed hinge pins with a one-hand manipulated tool. It has the purpose of removing headed hinge pins as further hereafter described. U. S. Pat. No. 4,188,701 Ludwig shows a hand-held tool which is constructed to assist in the removal of headed hinge pins of the type found in common building construction. The tool is constructed to be driven in under the head of the hinge pin while being held on an axis generally parallel to the hinge pin and in close proximity and juxtaposed thereto. When the tool is in position it is struck with a hammer first laterally to get it under the head of the hinge pin and then vertically to drive the hinge pin out of the hinge trunions.
There are several disadvantages in the use of this reference device which would make it unsuitable for use in removing hinge pins from unibody constructed automobile hinges.
In the first instance, it is necessary in the removal of steel body hinge pins to provide severe and heavy forces because the hinge pins are press-fitted and formed into the trunions. This is borne out by the prior two references Teske and Monteleone et al. which are operated by air hammers capable of providing severe impact.
In the second instance, the holding position is in close proximity to the position where the hammer blows must be struck. This, while perhaps efficient, when light, tapping blows are being applied, but not as a hand-held position in close proximity to the place where heavy blows are being struck because it means that the operator's hand is in danger of being struck by the heavy blows that are necessary to remove a hinge pin. Most mechanics feel insecure with their hand positioned so close to the place where heavy sledge hammer-like blows must be delivered. One misstruck blow and the operator's hand would be severely injured.
U. S. Pat. No. 3,602,969 Provost is another example of a similarly oriented hinge pin removing device for use in building construction and on building doors. It suffers from the same deficiencies as the previous patent when considered in the light of removing press-fitted hinge pins from vehicle doors.